Fuel feed controlling mechanism



Dec. 8, 1931.

aRouK FUEL FEED CONTROLLING MECHANISM Filed March 1, 1930 ATTORNEYS.-

Patented Dec. 8, 1931 ERICK ROUEKA, F BLANSKO, CZECHOSLOVAKIA FUEL FEED CONTROLLING MECHANISM Application filed March 1, 1930, Serial No. 432,521, and in Czechoslovakia March 8, 1929.

This invention relates in general to apparatus for controlling the feeding of fuel to furnaces, and more particularly the invention is directed to the regulation of the grate speed or the rate of supply of fuel in traveling or chain grate furnaces.

Known apparatus of this general character includes means sensitive to temperature at the discharge end of the grate which controls means for actuating or moving'the grate so that the grate speed or rate of fuel supply is increased and decreased upon a fall and a rise respectively in the temperature at the dis charge end of the grate. However, this regulation is irregular and unsatisfactory because upon feeding movement of the grate a large amount of fuel is supplied before the temperature is raised sufliciently to stop the feed, and then so long a time elapse-s before the next feeding operation occurs that the fuel is too far consumed.

The primary object of my invention is to provide means for preventing or overcoming this hunting action of such apparatus so as to ensure regular and efiicient supply of fuel.

Another object is to provide in apparatus of the character described novel and improved means whereby the fuel supplymechanism, i. e., the traveling grate, is stoppedbefore the temperature caused by combustion of the fuel at the discharge end of the grate has risen suificiently to itself actuate the temperature sensitive means, so that an excessive fuel supply is prevented.

A further object is to provide novel and improved auxiliary means for heatingsaid temperature sensitive means and actuated upon starting of the fuel supplying mechanism to supplement the action of the temperature from fuel combustion on said sensitive means, to prevent hunting action of the apparatus.

Other objects are to provide in apparatus of this character including an electric motor for operating the fuel supplying mechanism controlled by a thermostatic switch sensitive to temperature at the discharge end of the grate, an electric heater for exerting an influence on said thermostatic switch in. addibeing controlled by said switch and connected in the circuit with and at the sametime as said electric motor; to provide such mechanism which shall be simple and inexpensive in construction and reliable in operation, and

to obtain other advantages and results as will be brought out by the following description. Referring to the accompanying drawing, the figure is a schematic sectional elevation of a fuel feed controlling mechanism embodying my invention.

For the purpose of illustrating the principles of my invention, I have shown it in connection with a furnace having a known type of traveling or chain grate 1 which is actuated by worm and worm wheel gearing 2 by an electric motor 3 which is connected to a source of electricity by line wires 4 through a switch 5 actuated into closed position'by an electromagnet 6 and its cooperating armature 7. The fuel is supplied at one end of the grate (not shown) by 'known means, such as a hopper, and the grate travels in the direction of the arrow, the fuel being consumed upon the grate and the ashes being discharged by action of gravity into an ash pit 7 8 at the end of the grate opposite the fuel supply. The fire line of the fuel upon the grate, that is, the discharge end of the mass of live coals, is designated 9,.and the position of this fire line varies from time to time, so moving toward the fuel supply end of the grate as the fuel is consumed and toward the discharge or ash pit end of the grate as the grate is actuated to supply additional fuel.

Above the discharge end of the grate at a position withrespect thereto corresponding to the position at which it is desired to maintain the fire line, is a member 10 through' which constantly circulates at uniform rate a fluid. for example water, from a supply tank 11 and a tube 12 to a receptacle 13 in which is secured at one end a bi-metallic or thermostatic strip- 14 carrying at one end a switch contact 15 connected by a wire 16 to one side of the electrical supply circuit 4. This fluid transmits heat from the fuel bed to the bi-metallic strip 14, and overflows from the receptacle 13. The switch contact 15 cooperates with a contact screw 17' which is connected to one terminal of the electromagnet 6 by a wire 18. The other terminal of the magnet is connected to the line wire 19. The switch 15, 17 is normally open, and the fluid passing through the member 10 and the tube 12 is heated by the fire at the fire line 9 on the grate. Obviously the temperature of the fluid will vary according to the position of this fire line. When the fire line recedes to the left of the figure toward the supply end of the grate, the temperature of the fluid in the member 10 falls so that the thermostatic strip 14 is flexed to close the contact 15, 17. This energizes the electromagnet 6 which attracts its armature 7 so as to close the switch 5 and start the motor 3 so as to actuate the grate 1 in the direction of the arrow, supply new fuel and move the fire line toward the right of the figure. After a time the temperature of the fluid in the member 10 rises due to the hotter fire directly beneath it resulting from movement of the fire line, whereupon the thermostatic strip 14 is flexed in the other direction to open the switch 15, 17 and throw the motor out of operation so as to stop movement of the grate. The switch 5 may be opened by a spring or other suitable means 20. This operation is irregular and unsatisfactory because such a long time is required to raise the temperature of the fluid in the member 10, and excessive amounts of fuel are supplied to the grate at long intervals.

One feature of my invention consists in the provision of means for accelerating the heating of the fluid upon starting of operation of the grate so that a more regular and etficient operation of the grate and supply of fuel is obtained. This means may comprise an electric heating coil 21 surrounding the tube 12 between the member 10 and the receptacle 13, said heating coil being connected in circuit with the motor 3 and controlled by the switch 5 so that the heater is thrown into circuit at the same time the motor starts operation of the grate. An adjustable rheostat 22 may be provided in the heater circuit.

With this construction, when the grate is started in operation as the result of recession of the fire line 9 and a consequent lowering of the temperature beneath the member 10,the heater 21 is thrown into circuit so as to supplement the heating action resulting from the fuel combustion upon the fluid in the tube 12. In other words, the fluid is brought to a temperature which will open the switch 15, 17 sooner than it would he were the heat from the fuel combustion alone relied on. Accordingly. the grate 1 is moved a shorter distance with my invention, an excessive supply of fuel is avoided, and the intervals between the fuel feeding movements of the grate are short and substantially uniform, so that the position of the fire line is maintained more steady and the suDDlv of fuel is more regular.

It should be understood that the invention may be embodied in various different apparatus without departing from the spirit or scope of the invention, and I do not desire to be understood as limiting myself except as required by the following claims when construed in the light of the prior art. I am aware of United States Patents Nos. 1,521,669 and 1,522,595, dated January 6, 1925 and January 13, 1925, respectively, and do not desire to be understood as attempting to claim such constructions.

Having thus described my invention, what I claim is: 1. A fuel feed controlling apparatus comprising mechanical grate mechanism for feeding fuel, means for periodically actuating said grate mechanism, controlling means for connecting and disconnecting said acutating means to and from a source of power, a temperature sensitive means for actuating said controlling means, means for transmitting heat from the fuel bed to said-temperature sensitive means for actuating the latter, and means operated in accordance with the fuel feed for producing a differential between the temperature at the fuel bed and the temperature actuating said temperature sensitive means.

2. A fuel feed controlling apparatus comprising mechanical grate mechanism for feeding fuel, means for periodically actuating said grate mechanism, thermostatic means actuated by variations in the temperature at a point in the fuel bed near the fire line for controlling said actuating means, means for transmitting heat from said point in the fuel bed to said thermostatic means, and means operated in accordance with the fuel feed for cooperating with said heat transmitting means to produce a differential between the temperature at said point and the temperature actuating said thermostatic means.

3. A fuel feed controlling apparatus comprising mechanical grate mechanism for feeding fuel, means for periodically actuating said grate mechanism, controlling means for connecting and disconnecting said actuating means to and from a source of power, a temperature sensitive means for actuating said controlling means, means for transmitting heat from the fuel bed to said temperature sensitive means for actuating the latter, and auxiliary means operated upon actuation of said grate mechanism for heating said heat transmitting means.

4. A fuel feed controlling apparatus comprising mechanical gratemechanism for feeding fuel. electric motor operated means for actuating said grate mechanism. a switch for connecting anddisconnecting said electric motor means to and from a source of electricity, thermostatic means for controlling said switch and actuated by variations in Hill - the fire line thereon, means sensitive to temerature variations resulting from changes In pos1t1on of said fire hne, means controlled by said temperature sensitlve means for supheater connected in circuit with said grate actuating means for heating said temperature sensitive means to supplement the effect of the temperature from' fuel combustion upon said sensitive means.

ERICH ROUCKA.

plying fuel to said grate, and means actuated in accordance with the fuel feed for accelerating the controlling'action of said temperature sensitive means.

6. In a fuel feed controlling apparatus for furnaces, a mechanical grate, movement of which causes a feeding of fuel thereto and upon which the combustion of fuel causes variations in the position of the fire line thereon, means for actuating said grate, means sensitive to temperature variations resulting from changes in position of said fire line for controlling said actuatingmeans, and means actuated upon operation of said grate for accelerating the controlling action of said temperature sensitive means.

7. In a fuel feed controlling apparatus for furnaces, a grate upon which the'combustion of fuel causes variations in the osition of the fire line thereon, means sensitive to temperature variations resulting from changes in position of said fire line, means a controlled by said temperature sensitive means for supplying fuel to said grate, and means actuated in accordance with the fuel feed for heating said temperature sensitive I means to supplement the effect of the temperature of the fire line upon said sensitive means.

8. In a fuel feed controlling apparatus for furnaces, a mechanical grate, movement of which causes a feeding of fuel thereto and upon which the combustion of fuel causes variations in the position of the fire line thereon, means for actuating said grate,

means sensitive to temperature variations re-m I sulting from changes in position of said d line for controlling said actuating means,

. means actuated upon operation of said grate for heating'said temperature sensitive means to supphnent the efiect of the temperature from fuel-combustion upon said sensitive means. 1

9. In a fuel feed controlling apparatus for furnaces,- a mechanical grate, movement of which causes a feeding of fuel thereto and upon which the combustion of fuel causes variations in the position of the fire line thereon, electrically operated means for actuating said grate, a source of electricity, means sensitive to temperature variations resulting from changes in the position of said fire line for controlling the supply of electricity to said grate actuating means, and an electrical 

